Leukemia vaccine overcomes limitations of checkpoint blockade by evoking clonal T cell responses in a murine acute myeloid leukemia model

Emerging nanocarriers as advanced delivery tools for the treatment of leukemia

The most common type of blood cancer, leukemia, presents global therapeutic challenges like heterogeneity regarding age, sex, race, and a multiple pool of oncogenes and their complex network. In the last few years, nanotechnology has become the potential solution in leukemic resistance, chemotherapeutic failure, and disease-remission risk. Interestingly, the nanocarriers alone sometimes cannot overcome leukemia's obstacles, which demands a more advanced flagship in the nanocarrier segment like modification of the nanocarrier system, external stimuli for synergistic antileukemic effect, etc. This review has highlighted the need for emerging nanocarriers like exosome-like vesicles, nanodiamonds, nanoflower, etc. and biomimetic nanocarriers that reach the bone marrow niche. Notably, the role of nanoparticle-based vaccines in a disease-remission-free life and novel technology for nanocarrier delivery (microfluidics and plasmonic nanobubbles) have been discussed. This review also focuses on the clinical transition barriers of nanocarriers from the research laboratory. The continual research on novel nanocarriers and integration of new technologies to deliver the nanocarriers in the right way is paving the path for enhanced selectivity and efficacy in leukemia. The promising results in precise drug delivery and leukemic cell destruction are showing its great clinical prospects.

Single-cell RNA Sequencing Contributes to the Treatment of Acute Myeloid Leukaemia With Hematopoietic Stem Cell Transplantation, Chemotherapy, and Immunotherapy

Acute myeloid leukemia (AML) is caused by altered maturation and differentiation of myeloid blasts, as well as transcriptional/epigenetic alterations and impaired apoptosis, all of which lead to excessive proliferation of malignant blood cells in the bone marrow. It is these mutations that cause tumor heterogeneity, which is linked to a higher risk of relapse and death and makes anti-AML treatments like HSCT, chemotherapy, and immunotherapy (ICI, CAR T-cell-based therapies, and cancer vaccines) less effective. Single-cell RNA sequencing (scRNA-seq) also makes it possible to find cellular subclones and profile tumors, which opens up new diagnostic and therapeutic targets for better AML management. The HSCT process works better when genetic and transcriptional information about the patient and donor stem cells is collected. This saves time and lowers the risk of harmful side effects happening in the body.

A review of common immunotherapy and nano immunotherapy for acute myeloid leukemia

Acute myeloid leukemia (AML) is a highly aggressive hematological malignancy. Traditional chemotherapy methods not only bring serious side effects, but also lead to high recurrence rate and drug resistance in some patients. However, as an emerging therapeutic strategy, immunotherapy has shown great potential in the field of AML treatment in recent years. At present, common immunotherapy methods for AML include monoclonal antibodies, CAR-T cell therapy, and immune checkpoint inhibitors. With the deepening of research and technological progress, especially the application of nanotechnology in medicine, new immunotherapy is expected to become one of the important means for the treatment of acute myeloid leukemia in the future.

Revolutionizing cancer treatment: The power of dendritic cell-based vaccines in immunotherapy

In the modern time, cancer immunotherapies have increasingly become vital treatment options, joining long-established methods like surgery, chemotherapy, and radiotherapy treatment. Central to this emerging approach are dendritic cells (DCs), which boast a remarkable ability for antigen presentation. This ability is being leveraged to modulate T and B cell immunity, offering a groundbreaking strategy for tackling cancer. However, the percentage of patients experiencing meaningful benefits from this treatment remains relatively low, underscoring the ongoing necessity for further research and development in this field. This review offers a comprehensive analysis of the present-day progress in dendritic cell (DC)-based vaccines and recent efforts to enhance their efficacy. We explore the intricacies of DC function, from antigen capture to T cell stimulation, and discuss the outcomes of both preclinical and clinical trials across various cancer types. While the results are promising, the real-world application of DC-based vaccines is still nascent, posing multiple challenges that need to be overcome. These obstacles include optimizing the methods for DC generation and antigen loading, overcoming the immunosuppressive nature of the tumor microenvironment, and enhancing specificities of the immunologic response through personalized vaccines. The review concludes by emphasizing prospective opportunities for future research and emphasizing the critical need for extensive clinical trials. These trials are essential to validate the effectivity of DC-based vaccines and solidify their role in the broader spectrum of cancer immunotherapy options.

Single cell RNA sequencing improves the next generation of approaches to AML treatment: challenges and perspectives

Acute myeloid leukemia (AML) is caused by altered maturation and differentiation of myeloid blasts, as well as transcriptional/epigenetic alterations, all leading to excessive proliferation of malignant blood cells in the bone marrow. Tumor heterogeneity due to the acquisition of new somatic alterations leads to a high rate of resistance to current therapies or reduces the efficacy of hematopoietic stem cell transplantation (HSCT), thus increasing the risk of relapse and mortality. Single-cell RNA sequencing (scRNA-seq) will enable the classification of AML and guide treatment approaches by profiling patients with different facets of the same disease, stratifying risk, and identifying new potential therapeutic targets at the time of diagnosis or after treatment. ScRNA-seq allows the identification of quiescent stem-like cells, and leukemia stem cells responsible for resistance to therapeutic approaches and relapse after treatment. This method also introduces the factors and mechanisms that enhance the efficacy of the HSCT process. Generated data of the transcriptional profile of the AML could even allow the development of cancer vaccines and CAR T-cell therapies while saving valuable time and alleviating dangerous side effects of chemotherapy and HSCT in vivo. However, scRNA-seq applications face various challenges such as a large amount of data for high-dimensional analysis, technical noise, batch effects, and finding small biological patterns, which could be improved in combination with artificial intelligence models.

Therapeutic Vaccines for Hematological Cancers: A Scoping Review of This Immunotherapeutic Approach as Alternative to the Treatment of These Malignancies

Background/Objectives: The need for innovative cancer treatments has brought immunotherapies to the forefront as a promising approach, with therapeutic vaccines demonstrating the potential to mobilize immune cells to eliminate tumor cells. However, challenges such as genetic variability among patients, immune evasion mechanisms, and disease relapse contribute to the complexity of achieving an ideal therapy, especially for hematological cancers. This review systematically identifies and analyzes recent studies focused on the development of therapeutic immunotherapy vaccines, examining critical aspects such as development stages, key assays for therapeutic validation, treatment outcomes, and study limitations. Methods: A scoping review was conducted following the PRISMA extension guidelines (PRISMA-ScR). Literature searches were conducted across Scopus, PubMed, Web of Science, and Science Direct databases using keywords including "immunotherapy", "vaccines", "immunization", "hematological malignancies", "blood cancer", "hematopoietic neoplasms", and "leukemia". Results: A total of 56 articles published from 2013 to 2024 were included in the analysis. The majority of studies are in the preclinical stage, with some advancing to phase 1 and phase 2 clinical trials. Acute myeloid leukemia emerged as the most frequently studied malignancy. While first- and second-generation vaccines dominate the field, innovative approaches, such as dendritic-cell-based vaccines and mRNA vaccines, are gaining prominence. Notably, preclinical models often demonstrate superior outcomes compared to clinical trials, as results observed in animal models are not fully replicated in human studies. Conclusions: Despite challenges related to disease progression and patient loss, the studies reviewed highlight significant advancements in patient prognosis, emphasizing the potential of novel therapeutic vaccines as an effective alternative for the treatment of hematological cancers.

Targeting PRMT9-mediated arginine methylation suppresses cancer stem cell maintenance and elicits cGAS-mediated anticancer immunity

Current anticancer therapies cannot eliminate all cancer cells, which hijack normal arginine methylation as a means to promote their maintenance via unknown mechanisms. Here we show that targeting protein arginine N-methyltransferase 9 (PRMT9), whose activities are elevated in blasts and leukemia stem cells (LSCs) from patients with acute myeloid leukemia (AML), eliminates disease via cancer-intrinsic mechanisms and cancer-extrinsic type I interferon (IFN)-associated immunity. PRMT9 ablation in AML cells decreased the arginine methylation of regulators of RNA translation and the DNA damage response, suppressing cell survival. Notably, PRMT9 inhibition promoted DNA damage and activated cyclic GMP-AMP synthase, which underlies the type I IFN response. Genetically activating cyclic GMP-AMP synthase in AML cells blocked leukemogenesis. We also report synergy of a PRMT9 inhibitor with anti-programmed cell death protein 1 in eradicating AML. Overall, we conclude that PRMT9 functions in survival and immune evasion of both LSCs and non-LSCs; targeting PRMT9 may represent a potential anticancer strategy.

Dendritic cells as orchestrators of anticancer immunity and immunotherapy

Dendritic cells (DCs) are a heterogeneous group of antigen-presenting innate immune cells that regulate adaptive immunity, including against cancer. Therefore, understanding the precise activities of DCs in tumours and patients with cancer is important. The classification of DC subsets has historically been based on ontogeny; however, single-cell analyses are now additionally revealing a diversity of functional states of DCs in cancer. DCs can promote the activation of potent antitumour T cells and immune responses via numerous mechanisms, although they can also be hijacked by tumour-mediated factors to contribute to immune tolerance and cancer progression. Consequently, DC activities are often key determinants of the efficacy of immunotherapies, including immune-checkpoint inhibitors. Potentiating the antitumour functions of DCs or using them as tools to orchestrate short-term and long-term anticancer immunity has immense but as-yet underexploited therapeutic potential. In this Review, we outline the nature and emerging complexity of DC states as well as their functions in regulating adaptive immunity across different cancer types. We also describe how DCs are required for the success of current immunotherapies and explore the inherent potential of targeting DCs for cancer therapy. We focus on novel insights on DCs derived from patients with different cancers, single-cell studies of DCs and their relevance to therapeutic strategies.

Randomized Phase II Trial of Dendritic Cell/Myeloma Fusion Vaccine with Lenalidomide Maintenance after Upfront Autologous Hematopoietic Cell Transplantation for Multiple Myeloma: BMT CTN 1401

PURPOSE

Vaccination with dendritic cell (DC)/multiple myeloma (MM) fusions has been shown to induce the expansion of circulating multiple myeloma-reactive lymphocytes and consolidation of clinical response following autologous hematopoietic cell transplant (auto-HCT).

PATIENTS AND METHODS

In this randomized phase II trial (NCT02728102), we assessed the effect of DC/MM fusion vaccination, GM-CSF, and lenalidomide maintenance as compared with control arms of GM-CSF and lenalidomide or lenalidomide maintenance alone on clinical response rates and induction of multiple myeloma-specific immunity at 1-year posttransplant.

RESULTS

The study enrolled 203 patients, with 140 randomized posttransplantation. Vaccine production was successful in 63 of 68 patients. At 1 year, rates of CR were 52.9% (vaccine) and 50% (control; P = 0.37, 80% CI 44.5%, 61.3%, and 41.6%, 58.4%, respectively), and rates of VGPR or better were 85.3% (vaccine) and 77.8% (control; P = 0.2). Conversion to CR at 1 year was 34.8% (vaccine) and 27.3% (control; P = 0.4). Vaccination induced a statistically significant expansion of multiple myeloma-reactive T cells at 1 year compared with before vaccination (P = 0.024) and in contrast to the nonvaccine arm (P = 0.026). Single-cell transcriptomics revealed clonotypic expansion of activated CD8 cells and shared dominant clonotypes between patients at 1-year posttransplant.

CONCLUSIONS

DC/MM fusion vaccination with lenalidomide did not result in a statistically significant increase in CR rates at 1 year posttransplant but was associated with a significant increase in circulating multiple myeloma-reactive lymphocytes indicative of tumor-specific immunity. Site-specific production of a personalized cell therapy with centralized product characterization was effectively accomplished in the context of a multicenter cooperative group study. See related commentary by Qazilbash and Kwak, p. 4703.

Targeting chemoresistance and mitochondria-dependent metabolic reprogramming in acute myeloid leukemia

Chemoresistance often complicates the management of cancer, as noted in the instance of acute myeloid leukemia (AML). Mitochondrial function is considered important for the viability of AML blasts and appears to also modulate chemoresistance. As mitochondrial metabolism is aberrant in AML, any distinct pathways could be directly targeted to impact both cell viability and chemoresistance. Therefore, identifying and targeting those precise rogue elements of mitochondrial metabolism could be a valid therapeutic strategy in leukemia. Here, we review the evidence for abnormalities in mitochondria metabolic processes in AML cells, that likely impact chemoresistance. We further address several therapeutic approaches targeting isocitrate dehydrogenase 2 (IDH2), CD39, nicotinamide phosphoribosyl transferase (NAMPT), electron transport chain (ETC) complex in AML and also consider the roles of mesenchymal stromal cells. We propose the term "mitotherapy" to collectively refer to such regimens that attempt to override mitochondria-mediated metabolic reprogramming, as used by cancer cells. Mounting evidence suggests that mitotherapy could provide a complementary strategy to overcome chemoresistance in liquid cancers, as well as in solid tumors.

A Direct Comparison, and Prioritisation, of the Immunotherapeutic Targets Expressed by Adult and Paediatric Acute Myeloid Leukaemia Cells: A Systematic Review and Meta-Analysis

Acute myeloid leukaemia (AML) is characterized by impaired myeloid differentiation resulting in an accumulation of immature blasts in the bone marrow and peripheral blood. Although AML can occur at any age, the incidence peaks at age 65. The pathobiology of AML also varies with age with associated differences in incidence, as well as the frequency of cytogenetic change and somatic mutations. In addition, 5-year survival rates in paediatrics are 60-75% but fall to 5-15% in older AML patients. This systematic review aimed to determine whether the altered genes in AML affect the same molecular pathways, indifferent of patient age, and, therefore, whether patients could benefit from the repurposing drugs or the use of the same immunotherapeutic strategies across age boundaries to prevent relapse. Using a PICO framework and PRISMA-P checklist, relevant publications were identified using five literature databases and assessed against an inclusion criteria, leaving 36 articles, and 71 targets for therapy, for further analysis. QUADAS-2 was used to determine the risk of bias and perform a quality control step. We then priority-ranked the list of cancer antigens based on predefined and pre-weighted objective criteria as part of an analytical hierarchy process used for dealing with complex decisions. This organized the antigens according to their potential to act as targets for the immunotherapy of AML, a treatment that offers an opportunity to remove residual leukaemia cells at first remission and improve survival rates. It was found that 80% of the top 20 antigens identified in paediatric AML were also within the 20 highest scoring immunotherapy targets in adult AML. To analyse the relationships between the targets and their link to different molecular pathways, PANTHER and STRING analyses were performed on the 20 highest scoring immunotherapy targets for both adult and paediatric AML. There were many similarities in the PANTHER and STRING results, including the most prominent pathways being angiogenesis and inflammation mediated by chemokine and cytokine signalling pathways. The coincidence of targets suggests that the repurposing of immunotherapy drugs across age boundaries could benefit AML patients, especially when used in combination with conventional therapies. However, due to cost implications, we would recommend that efforts are focused on ways to target the highest scoring antigens, such as WT1, NRAS, IDH1 and TP53, although in the future other candidates may prove successful.

Guest Editorial: what can be done to improve cancer immunotherapies?

Cancer immunotherapies including immune checkpoint inhibitor and cell-based regimens such as chimeric antigen receptor T cell therapy have progressed markedly in the last decade. However, the efficacy of those cancer immunotherapies is still limited in some patient populations due to the many mechanisms of antitumor immunomodulation, including immune checkpoint molecules expressed by both tumor cells and the tumor microenvironment, immunosuppressive cells, and tumor cell-derived factors such as extracellular vesicles. In this PIH review series, we focus on new knowledge and strategies to improve immunotherapies for cancer patients.

Immune Reconstitution and Vaccinations in Multiple Myeloma: A Report From the 19th International Myeloma Society Annual Workshop

Given the significance of the immune system and the important role of therapies within the context of the immune system in plasma cell disorders, the International Myeloma Society annual workshop convened a session dedicated to this topic. A panel of experts covered various aspects of immune reconstitution and vaccination. The top oral presentations were highlighted and discussed. This is a report of the proceedings.

A perspective of immunotherapy for acute myeloid leukemia: Current advances and challenges

During the last decade, the underlying pathogenic mechanisms of acute myeloid leukemia (AML) have been the subject of extensive study which has considerably increased our understanding of the disease. However, both resistance to chemotherapy and disease relapse remain the principal obstacles to successful treatment. Because of acute and chronic undesirable effects frequently associated with conventional cytotoxic chemotherapy, consolidation chemotherapy is not feasible, especially for elderly patients, which has attracted a growing body of research to attempt to tackle this problem. Immunotherapies for acute myeloid leukemia, including immune checkpoint inhibitors, monoclonal antibodies, dendritic cell (DC) vaccines, together with T-cell therapy based on engineered antigen receptor have been developed recently. Our review presents the recent progress in immunotherapy for the treatment of AML and discusses effective therapies that have the most potential and major challenges.

Dendritic Cell-Triggered Immune Activation Goes along with Provision of (Leukemia-Specific) Integrin Beta 7-Expressing Immune Cells and Improved Antileukemic Processes

Integrin beta 7 (β7), a subunit of the integrin receptor, is expressed on the surface of immune cells and mediates cell-cell adhesions and interactions, e.g., antitumor or autoimmune reactions. Here, we analyzed, whether the stimulation of immune cells by dendritic cells (of leukemic derivation in AML patients or of monocyte derivation in healthy donors) leads to increased/leukemia-specific β7 expression in immune cells after T-cell-enriched mixed lymphocyte culture-finally leading to improved antileukemic cytotoxicity. Healthy, as well as AML and MDS patients' whole blood (WB) was treated with Kit-M (granulocyte-macrophage colony-stimulating factor (GM-CSF) + prostaglandin E1 (PGE1)) or Kit-I (GM-CSF + Picibanil) in order to generate DCs (DC_leu or monocyte-derived DC), which were then used as stimulator cells in MLC. To quantify antigen/leukemia-specific/antileukemic functionality, a degranulation assay (DEG), an intracellular cytokine assay (INTCYT) and a cytotoxicity fluorolysis assay (CTX) were used. (Leukemia-specific) cell subtypes were quantified via flow cytometry. The Kit treatment of WB (compared to the control) resulted in the generation of DC/DC_leu, which induced increased activation of innate and adaptive cells after MLC. Kit-pretreated WB (vs. the control) led to significantly increased frequencies of β7-expressing T-cells, degranulating and intracellular cytokine-producing β7-expressing immune cells and, in patients' samples, increased blast lysis. Positive correlations were found between the Kit-M-mediated improvement of blast lysis (vs. the control) and frequencies of β7-expressing T-cells. Our findings indicate that DC-based immune therapies might be able to specifically activate the immune system against blasts going along with increased frequencies of (leukemia-specific) β7-expressing immune cells. Furthermore, β7 might qualify as a predictor for the efficiency and the success of AML and/or MDS therapies.

Immunotherapy approaches for hematological cancers

Hematological cancers such as leukemia, lymphoma, and multiple myeloma have traditionally been treated with chemo and radiotherapy approaches. Introduction of immunotherapies for treatment of these diseases has led to patient remissions that would not have been possible with traditional approaches. In this critical review we identify main disease characteristics, symptoms, and current treatment options. Five common immunotherapies, namely checkpoint inhibitors, vaccines, cell-based therapies, antibodies, and oncolytic viruses, are described, and their applications in hematological cancers are critically discussed.

Plasmacytoid Dendritic Cells, a Novel Target in Myeloid Neoplasms

Plasmacytoid dendritic cells (pDC) are the main type I interferon producing cells in humans and are able to modulate innate and adaptive immune responses. Tumor infiltration by plasmacytoid dendritic cells is already well described and is associated with poor outcomes in cancers due to the tolerogenic activity of pDC. In hematological diseases, Blastic Plasmacytoid Dendritic Cells Neoplasm (BPDCN), aggressive leukemia derived from pDCs, is well described, but little is known about tumor infiltration by mature pDC described in Myeloid Neoplasms (MN). Recently, mature pDC proliferation (MPDCP) has been described as a differential diagnosis of BPDCN associated with acute myeloid leukemia (pDC-AML), myelodysplastic syndrome (pDC-MDS) and chronic myelomonocytic leukemia (pDC-CMML). Tumor cells are myeloid blasts and/or mature myeloid cells from related myeloid disorders and pDC derived from a clonal proliferation. The poor prognosis associated with MPDCP requires a better understanding of pDC biology, MN oncogenesis and immune response. This review provides a comprehensive overview about the biological aspects of pDCs, the description of pDC proliferation in MN, and an insight into putative therapies in pDC-AML regarding personalized medicine.

Trial watch: Dendritic cell (DC)-based immunotherapy for cancer

Dendritic cell (DC)-based vaccination for cancer treatment has seen considerable development over recent decades. However, this field is currently in a state of flux toward niche-applications, owing to recent paradigm-shifts in immuno-oncology mobilized by T cell-targeting immunotherapies. DC vaccines are typically generated using autologous (patient-derived) DCs exposed to tumor-associated or -specific antigens (TAAs or TSAs), in the presence of immunostimulatory molecules to induce DC maturation, followed by reinfusion into patients. Accordingly, DC vaccines can induce TAA/TSA-specific CD8+/CD4+ T cell responses. Yet, DC vaccination still shows suboptimal anti-tumor efficacy in the clinic. Extensive efforts are ongoing to improve the immunogenicity and efficacy of DC vaccines, often by employing combinatorial chemo-immunotherapy regimens. In this Trial Watch, we summarize the recent preclinical and clinical developments in this field and discuss the ongoing trends and future perspectives of DC-based immunotherapy for oncological indications.

Neoantigen Cancer Vaccines: Generation, Optimization, and Therapeutic Targeting Strategies

Alternatives to conventional cancer treatments are highly sought after for high-risk malignancies that have a poor response to established treatment modalities. With research advancing rapidly in the past decade, neoantigen-based immunotherapeutic approaches represent an effective and highly tolerable therapeutic option. Neoantigens are tumor-specific antigens that are not expressed in normal cells and possess significant immunogenic potential. Several recent studies have described the conceptual framework and methodologies to generate neoantigen-based vaccines as well as the formulation of appropriate clinical trials to advance this approach for patient care. This review aims to describe some of the key studies in the recent literature in this rapidly evolving field and summarize the current advances in neoantigen identification and selection, vaccine generation and delivery, and the optimization of neoantigen-based therapeutic strategies, including the early data from pivotal clinical studies.

Research progress on dendritic cell vaccines in cancer immunotherapy

Dendritic cell (DC) vaccines induce specific immune responses that can selectively eliminate target cells. In recent years, many studies have been conducted to explore DC vaccination in the treatment of hematological malignancies, including acute myeloid leukemia and myelodysplastic syndromes, as well as other nonleukemia malignancies. There are at least two different strategies that use DCs to promote antitumor immunity: in situ vaccination and canonical vaccination. Monocyte-derived DCs (mo-DCs) and leukemia-derived DCs (DCleu) are the main types of DCs used in vaccines for AML and MDS thus far. Different cancer-related molecules such as peptides, recombinant proteins, apoptotic leukemic cells, whole tumor cells or lysates and DCs/DCleu containing a vaster antigenic repertoire with RNA electroporation, have been used as antigen sources to load DCs. To enhance DC vaccine efficacy, new strategies, such as combination with conventional chemotherapy, monospecific/bispecific antibodies and immune checkpoint-targeting therapies, have been explored. After a decade of trials and tribulations, much progress has been made and much promise has emerged in the field. In this review we summarize the recent advances in DC vaccine immunotherapy for AML/MDS as well as other nonleukemia malignancies.

The EHA Research Roadmap: Immune-based Therapies for Hematological Malignancies

In 2016, the European Hematology Association (EHA) published the EHA Roadmap for European Hematology Research¹ aiming to highlight achievements in the diagnostics and treatment of blood disorders, and to better inform European policy makers and other stakeholders about the urgent clinical and scientific needs and priorities in the field of hematology. Each section was coordinated by 1-2 section editors who were leading international experts in the field. In the 5 years that have followed, advances in the field of hematology have been plentiful. As such, EHA is pleased to present an updated Research Roadmap, now including 11 sections, each of which will be published separately. The updated EHA Research Roadmap identifies the most urgent priorities in hematology research and clinical science, therefore supporting a more informed, focused, and ideally a more funded future for European Hematology Research. the 11 EHA Research Roadmap sections include normal hematopoiesis; malignant lymphoid diseases; malignant myeloid diseases; anemias and related diseases; platelet disorders; blood coagulation and hemostatic disorders; transfusion medicine; infections in hematology; hematopoietic stem cell transplantation; CAR-T and Other cell-based immune therapies; and gene therapy.